Tag Archives: Forager

Most animals in the world can’t be usefully domesticated. This isn’t because we can’t eat their meat, or feed them the food they need. It is because all animals naturally resist being dominated. Only rare social species can let a human sit in the role of dominant pack animal whom they will obey, and only if humans do it just right.

Most nations today would be richer if they had long ago just submitted wholesale to a rich nation, allowing that rich nation to change their laws, customs, etc., and just do everything their way. But this idea greatly offends national and cultural pride. So nations stay poor.

When firms and managers from rich places try to transplant rich practices to poor places, giving poor place workers exactly the same equipment, materials, procedures, etc., one of the main things that goes wrong is that poor place workers just refuse to do what they are told. They won’t show up for work reliably on time, have many problematic superstitions, hate direct orders, won’t accept tasks and roles that that deviate from their non-work relative status with co-workers, and won’t accept being told to do tasks differently than they had done them before, especially when new ways seem harder. Related complaints are often made about the poorest workers in rich societies; they just won’t consistently do what they are told. It seems pride is a big barrier to material wealth.

The farming mode required humans to swallow many changes that didn’t feel nice or natural to foragers. While foragers are fiercely egalitarian, farmers are dominated by kings and generals, and have unequal property and classes. Farmers work more hours at less mentally challenging tasks, and get less variety via travel. Huge new cultural pressures, such as religions with moralizing gods, were needed to turn foragers into farmers.

But at work farmers are mostly autonomous and treated as the equal of workers around them. They may resent having to work, but adults are mostly trusted to do their job as they choose, since job practices are standardized and don’t change much over time. In contrast, productive industrial era workers must accept more local domination and inequality than would most farmers. Industry workers have bosses more in their face giving them specific instructions, telling them what they did wrong, and ranking them explicitly relative to their previous performance and to other nearby workers. They face more ambiguity and uncertainty about what they are supposed to do and how.

How did the industrial era get at least some workers to accept more domination, inequality, and ambiguity, and why hasn’t that worked equally well everywhere? A simple answer I want to explore in this post is: prestigious schools.

While human foragers are especially averse to even a hint of domination, they are also especially eager to take “orders” via copying the practices of prestigious folks. Humans have a uniquely powerful capacity for cultural evolution exactly because we are especially eager and able to copy what prestigious people do. So if humans hate industrial workplace practices when they see them as bosses dominating, but love to copy the practices of prestigious folks, an obvious solution is to habituate kids into modern workplace practices in contexts that look more like the latter than the former.

In his upcoming book, The Case Against Education, my colleague Bryan Caplan argues that school today, especially at the upper levels, functions mostly to help students signal intelligence, conscientiousness, and conformity to modern workplace practices. He says we’d be better off if kids did this via early jobs, but sees us as having fallen into an unfortunate equilibrium wherein individuals who try that seem non-conformist. I agree with Bryan that, compared with the theory that older students mostly go to school to learn useful skills, signaling better explains the low usefulness of school subjects, low transfer to other tasks, low retention of what is taught, low interest in learning relative to credentials, big last-year-of-school gains, and student preferences for cancelled classes.

My main problem with Caplan’s story so far (he still has time to change his book) is the fact that centuries ago most young people did signal their abilities via jobs, and the school signaling system has slowly displaced that job signaling system. Pressures to conform to existing practices can’t explain this displacement of a previous practice by a new practice. So why did signaling via school did win out over signaling via early jobs?

Like early jobs, school can have people practice habits that will be useful in jobs, such as showing up on time, doing what you are told even when that is different from what you did before, figuring out ambiguous instructions, and accepting being frequently and publicly ranked relative to similar people. But while early jobs threaten to trip the triggers than make most animals run from domination, schools try to frame a similar habit practice in more acceptable terms, as more like copying prestigious people.

Forager children aren’t told what to do; they just wander around and do what they like. But they get bored and want to be respected like adults, so eventually they follow some adults around and ask to be shown how to do things. In this process they sometimes have to take orders, but only until they are no longer novices. They don’t have a single random boss they don’t respect, but can instead be trained by many adults, can select them to be the most prestigious adults around, and can stop training with each when they like.

Schools work best when they set up an apparently similar process wherein students practice modern workplaces habits. Start with prestigious teachers, like the researchers who also teach at leading universities. Have students take several classes at at a time, so they have no single “boss” who personally benefits from their following his or her orders. Make class attendance optional, and let students pick their classes. Have teachers continually give students complex assignments with new ambiguous instructions, using the excuse of helping students to learn new things. Have lots of students per teacher, to lower costs, to create excuses for having students arrive and turn in assignments on time, and to create social proof that other students accept all of this. Frequently and publicly rank student performance, using the excuse of helping students to learn and decide which classes and jobs to take later. And continue the whole process well into adulthood, so that these habits become deeply ingrained.

When students finally switch from school to work, most will find work to be similar enough to transition smoothly. This is especially true for desk professional jobs, and when bosses avoid giving direct explicit orders. Yes, workers now have one main boss, and can’t as often pick new classes/jobs. But they won’t be publicly ranked and corrected nearly as often as in school, even though such things will happen far more often than their ancestors would have tolerated. And if their job ends up giving them prestige, their prior “submission” to prestigious teachers will seem more appropriate.

This point of view can help explain how schools could help workers to accept habits of modern workplaces, and thus how there could have been selection for societies that substituted schools for early jobs or other child activities. It can also help explain unequal gains from school; some kinds of schools should be less effective than others. For example, teachers might not be prestigious, teachers may fail to show up on time to teach, teacher evaluations might correlate poorly with student performance, students might not have much choice of classes, school tasks might diverge too far from work tasks, students may not get prestigious jobs, or the whole process might continue too long into adulthood, long after the key habituation has been achieved.

In sum, while students today may mostly use schools to signal smarts, drive, and conformity, we need something else to explain how school displaced early work in this signaling role. One plausible story is that schools habituate students in modern workplace habits while on the surface looking more like prestigious forager teachers than like the dominating bosses that all animals are primed to resist. But this hardly implies that everything today that calls itself a school is equally effective at producing this benefit.

Rightism is what happens when you’re optimizing for surviving an unsafe environment, leftism is what happens when you’re optimized for thriving in a safe environment. … “Take actions that would be beneficial to survival in case of a zombie apocalypse” seems to get us rightist positions on a lot of issues. We can generalize from zombie apocalypses to any desperate conditions in which you’re not sure that you’re going to make it and need to succeed at any cost.

What about the opposite? Let’s imagine a future utopia of infinite technology. Robotic factories produce far more wealth than anyone could possibly need. … Even death itself has disappeared. What policies are useful for this happy state? …

If the brain finds itself in a stable environment where everything is abundant, it sort of lowers the mental threat level and concludes that everything will always be okay and its job is to enjoy itself and win signaling games. If it finds itself in an environment of scarcity, it will raise the mental threat level and set its job to “survive at any cost”. … Leftism wins over time because technology advances over time which means societies become more secure and abundant over time. …

Both Greece and Rome were relatively leftist, with freedom of religion, democratic-republican governments, weak gender norms, minimal family values, and a high emphasis on education and abstract ideas. After the Fall of Rome, when Europe was set back technologically into a Dark Age, rightism returned with a vengeance. …

“So you mean rightism is optimized for tiny unstable bands facing a hostile wilderness, and leftism is optimized for secure, technologically advanced societies like the ones we are actually in?” And this conclusion, too, I will mostly endorse. (more)

Much of this is pretty compatible with the forager-farmer perspective I outlined in 2010. To review, as foragers our attitudes and inclinations were well adapted to our environment, but the farming environment was so different that to become effective farmers we had to drastically change such things in a short time. So we cranked up the pressure on social conformity, religion, etc. in order to enforce strong new social norms favoring new farming behaviors. But because these were built on fear, and went somewhat against our deeper natures, rich safe elites have often drifted back toward forager styles, and the whole world has drifted that way together since we’ve all gotten rich and safe with industry. This view makes sense of many long term trends over the last few decades, such as trends toward more leisure, travel, product variety, egalitarianism, democracy, peace, and slavery aversion.

However, in addition to the forager-farmer or survive-thrive distinction, there is another related distinction that I think I, and Scott above, haven’t been thinking clearly enough about. And that is the distinction between supporting specific ways of foragers and farmers, and generalizing their attitudes toward simpler more general principles. Let me explain. Continue reading "Specific vs. General Foragers & Farmers" »

Based on Bryan’s recommendation, I’ve been reading the excellent Promises I Can Keep (quotes below), an ethnography of mating patterns among poor folks in Philadelphia. I greatly respect ethnographies, and intend to read more of them (suggestions welcome).

Poverty isn’t about money; it’s a state of mind. That state of mind is low conscientiousness.

But that doesn’t seem quite right to me – the situation is better summarized as the poor having different social norms on appropriate kinds of romantic commitment. Yes these norms may promote and be better matched to low conscientiousness, but even so it is the norms that are the direct effect. Let me explain.

All societies have romantic/sexual pair-bonds, i.e., pairs of people with a special distinguished relation. But societies vary in their types and levels of commitment. Consider these options:

We see each other recently more often than do random pairs.

We act as if we expect our relation to be exclusive.

We act as if we expect our relation to last a long time.

We tell associates that we expect a long/exclusive relation, and will be embarrassed if we are seen to be wrong.

We invest in shared kids, friends, habits which are degraded if we split.

We spent lots on a feast/ceremony to signal our long/exclusive relation, and can’t afford to do that again for a long time.

Our community will see us as immoral and somewhat shame us if we split.

We invest in relationship-specific capital that is degraded if we split, such as housing or a division of labor.

We have transferable assets held hostage that we forfeit if we leave.

Our community will use force to prevent one of us from leaving, if the other asks.

Societies vary in which types of commitment they see as fitting when. Traditional farming cultures have used all of these ways to bond couples together. In contrast, traditional forager cultures typically only used levels #1,2 while young, and then added in only #3,4,5 when older. They didn’t use the rest.

The lower class US culture described in Promises I Can Keep have mostly reverted back to forager ways. When young they basically only use #1,2, and eagerly have kids in that mode, which adds some of #5. When older they often formally marry which adds #3,4,5,6,7, but not #8,9,10. This is all done on purpose. When young they talk explicitly about wanting kids but not wanting to be tied to a particular partner, so they can switch when the mood strikes them. They see marriage as a way to brag about life success, which must await their achieving most of their life goals, including a house, career success, etc. Usually men push for marriage, and women resist. Before marriage, women enjoy pretty complete control over kids.

Upper class US culture, in contrast, has a youthful dating period with only #1,2 but expects kids to wait for marriage which adds #3,4,5,6,7. This culture still has elements of #8,9,10, but those are increasingly disapproved, and this culture is moving away from those. So our entire culture has been moving from farmer toward forager norms as we’ve become richer, but the richer among us are those whose norms have moved slower in that direction. This is understandable if some people and subcultures more strongly feel the social pressures that made foragers into farmers, and if farming norms and styles tend to cause more wealth today.

The obvious near term prediction is that as wealth continues to increase, we’ll see a continuing move toward forager mating habits and norms within all classes.

Forager food sources tended to be more risky and variable, while farmer food sources are more reliable. So foragers emphasized food sharing more, and a tolerate attitude toward failure to find food. In contrast, farmers shared food less and held individuals responsible more for getting their food. We’ve even seen the same people switch from one attitude to the other as they switched from foraging to farming. Today some people and places tend more toward farmer values of strict personal responsibility, while other people and places tend more toward forager forgiveness.

McArdle’s book is interesting throughout. For example, she talks about how felons on parole are dealt with much better via frequent reliable small punishments, relative to infrequent random big punishments. But when it comes to bankruptcy law, a situation where the law can’t help but wait a long time to respond to an accumulation of small failures, McArdle favors forager forgiveness. She points out that this tends to encourage folks who start new businesses, which encourages more innovation. And this doesindeed seem to be a good thing.

Folks who start new businesses are pretty rare, however, and it is less obvious to me that more leniency is good overall. It is not obvious that ordinary people today face more risk than did most farmers during the farming era. The US apparently has the most lenient bankruptcy law in the world, and that is indeed some evidence for its value. However, it seems to me more likely that US forager forgiveness was caused by US wealth than vice versa. McArdle says the US got lenient bankruptcy in the late 1800s via lobbying by senators representing western farmers in debt to eastern banks. And it is even harder to see how farming in the US west then was more risky than has been farming throughout the whole farming era.

Most likely what changed was the wealth of US farmers, and their new uppity attitudes toward rich elites. This fits with debt-forgiveness being a common liberal theme, which fits with liberal attitudes being more forager-like, and becoming more common as rising wealth cut the fear that made farmers. If lenient bankrupts is actually better for growth in our world, this would be another example of Caplan’s idea trap, where rising wealth happens to create better attitudes toward good policy.

Overall I found it very hard to disagree with anything that McArdle said in her book. If you know me, that is quite some praise. 🙂

Added 2May: The fact that most farmer cultures were clannish may be part of an explanation here. The strict farmer morality is mostly about how to deal with outsiders, distant from your immediate family. The clan is punished severely, but it is usually more forgiving internally. If farmer clans had lower risk than do isolated families today, that could be a reason to have more forgiving bankruptcy law today.

When a cause seems good, a variation focused on children seems better. For example, if volunteering at a hospital is good, volunteering at a children’s hospital is better. If helping Africa is good, helping African kids is better. If teaching people to paint is good, teaching children to paint is better. If promoting healthy diets is good, promoting healthy diets in kids is better. If protecting people from war is good, protecting kids from war is better. If comforting lonely people is good, comforting lonely kids is better.

Why do most idealistic causes seem better when directed at kids? One explanation is that kids count a lot more in our moral calculus, just as humans count more than horses. But most would deny this I think. Another explanation is that kids just consistently need more of everything. But this just seems wrong. Kids are at the healthiest ages, for example, and so need health help the least. Even so, children health is considered a very noble cause.

For our foragers ancestors, child rearing was mostly a communal activity, at least after the first few years. So while helping to raise kids was good for the band overall, each individual might want to shirk on their help, and let others do the work. So forager bands would try to use moral praise and criticism to get each individual to do their kid-raising share. This predicts that doing stuff for kids would seem especially moral for foragers. And maybe we’ve retained such habits.

My favored explanation, however, is that people today typically do good in order to seem kind, in order to attract mates. If potential mates are considering raising kids with you, then they care more about your kindness toward kids than about your kindness toward others. So to show off the sort of kindness that your audience cares about, you put a higher priority on kindness to kids.

Of course if you happened to be one of those exceptions really trying to just to make the world a better place, why you’d want to correct for this overemphasis on kids by avoiding them. You’d want to help anyone but kids. And now that you all know this, I’ll wait to hear that massive rumbling from the vast stampeed of folks switching their charity away from kids. … All clear, go ahead. … Don’t be shy …

Many reality TV shows, like Project Runway, Hell’s Kitchen, or Survivor, focus on punishing the worst, instead of rewarding the best. Not only do viewers seem to find that more interesting, it actually works better to incentivize performance (many quotes below). Punishment works better to encourage lone behavior, to encourage behavior in a group, and as a tool for letting some group members encourage others.

The puzzle is that in most of our social worlds we instead focus on rewarding the best, not punishing the worst. If you search for “punish reward” you will mostly find the issue raised about how to treat kids; we are mainly willing to use punishment flexibly on them. And this when young kids are the main exception – for them punishment works worse. For adults, we tend to limit punishment’s use to extreme behavior that we all strongly agree is bad, like crime. And when you ask adults, they much prefer to be part of a group that uses rewards, not punishment.

As a college teacher, I expect that I’d get more effort from most students by regularly pointing out the worst student in the class than the best. But I also expect students to hate it and give me low evaluations. Similarly, I expect that if I wrote the occasional post criticizing a bad blog commenter here, instead of praising a good one, I’d get more change in commenting behavior. But I also expect that person to complain long and loud about how I was biased and unfair, and others to come to their defense. I expect a lot less complaining about bias in picking the best.

In both the class and comment cases, I expect people to see me as mean and cruel for punishing the worst, but kind and generous for rewarding the best. This even though all of these effects are relative – punishment would raise the rest of the class, or the rest of the commenters, up above the worse.

Note that rewarding the best is in practice more elitist than punishing the worse; punishing creates an underclass, not an overclass. And in fact our hyper-egalitarian forager ancestors were quite reluctant to overtly reward or praise; they focused their social coordination on having the group punish norm violators. Our hyper sensitivity to being punished, and our elaborate instinctual strategies to give excuses and to coordinate to retaliate against any who might suggest we should be punished, are probably human adaptations to that forager history. And they make us especially unwilling to accept punishment by an authority, instead of by the informal consensus of the group.

This seems an interesting example of our seeking to avoid aspects of the forager way of life. Our forager evolved aversion to being singled out for social shame is so strong that we’d rather create elites instead. At least this applies when we are relatively rich and comfortable. If we really feared being destroyed for lack of sufficient efforts, as farmers often did, we’d probably be a lot more eager to raise overall efforts by punishing the worse. I suspect that foragers themselves didn’t punish much in good times; punishment was invoked more, and mattered more, in hard times. In good times foragers probably more tolerated praising some as better, and weak forms of bragging.

In a more competitive future, with organizations and individuals that compete harder to survive, I’d expect more use of punishment, in addition to reward.

Today if you have a group that really needs to succeed, and to induce strong efforts all around, consider paying the social disruptions costs of punishing the worst, instead of rewarding the best. You will probably get more effort that way, even if people end up hating you and calling you evil for it. And if your group doesn’t punish and fails, know that your reluctance to punish was probably a contributing factor.

Our past can be summarized as a sequence of increasingly fast eras: animals, foragers, farmers, industry. Foragers grew by a factor of about four hundred over two million years, farmers grew by a factor of about two hundred over ten thousand years, and the industry economy has so far grown by a factor of about eight hundred over three hundred years. If this trend continues then before this era grows by another factor of a thousand, our economy should transition to another even faster growing era.

I saw the latest Star Trek movie today. It struck me yet again that such stories, set two centuries in our future, imagine a unlikely continuation of industry era styles, trends, and growth rates. At current growth rates the economy would grow by a factor of two thousand over that time period. Yet their cities, homes, workplaces, etc. look quite recognizably industrial, and quite distinct from either farmer or forager era styles. The main ways their world is different from ours is in continuing industry era trends, such as to richer and healthier individuals, and to more centralized government.

While this seems unlikely, it does make sense as a way to engage the audiences of today. But it leads me to wonder: what if past eras had set stories in imagined futures where their era’s trends and styles had long continued?

For example, imagine that the industrial revolution had never happened, and that the farming era had continued for another ten thousand years, leading to more than today’s world population, mostly farming at subsistence incomes within farmer-era social institutions. Oh there’d be a lot of sci/tech advances, just not creating much industry. Perhaps they’d farm the oceans and skies, and have melted the poles. Following farmer era trends, there’d be less violence, and longer term planning horizons. There’d be a lot more thoughtful writings, but without much intellectual specialization having arisen. Towns and firms would also still be small and less specialized.

Or, imagine that the farming revolution had never happened, but that foragers had continued to advance for another two million years, also reaching a population like today. They’d still live in small wandering bands collecting wild food, but in a much wider range of environments. Maybe they’d forage the seas and the skies. Their brains would be bigger, their tools more advanced, and their culture of participatory dance, music, and stories far more elaborate.

These sound like fascinating worlds to imagine, and would make good object lessons as well. Our future may be as different from the world of Star Trek as these imagined worlds would be from our world today.

There have been three major eras of human history: foraging, farming, and industry. During each era our economy has grown at a roughly steady exponential rate, and I’ve written beforeabout some intriguing patterns in these growth eras: eras encompassed a similar number of doublings (~7-10), transitions between eras were much shorter than prior doubling times, and such transitions encompassed a similar number of growth rate doublings (~6-8). I’ve also noted that transition-induced inequality seems to have fallen over time.

I just noticed another intriguing pattern, this time in community sizes. Today in industrial societies roughly halfof the population lives in metropolitan areas with between one hundred thousand and ten million people, with a mid size of about a million. While good data seemshard to find, during the farming era most people seem to have lived in communities (usually centered around a village) of between roughly three hundred and three thousand people, with a mid size of about a thousand. Foragers typically lived in mobile bands of size roughly twenty to fifty, with a best size of about thirty.

So community sizes went roughly from thirty to a thousand to a million. The pattern here is that each new era had a typical community size that was roughly the square of the size during the previous era. That is, a city is roughly a village of villages, and a village is roughly a band of bands. We could extend this patter further if we liked, saying that an extended family group has about four to eight members, with a mid size of six, so that a band is a family of families. (We might even go further and say that a family is a couple of couples, where a couple has two or so members.)

If previous growth patterns were to continue, I’ve written beforethat a new growth era might appear sometime in roughly the next century, and over a few years the economy would transition to a new growth rate of doubling every week to month. If this newly-noticed community size pattern were to continue, the new era would have communities of size roughly a trillion, perhaps ranging from ten billion to a hundred trillion.

Admittedly, after a year or two of this new era, things might change again, to yet another era. And the growth and community size trends couldn’t both continue to that next era, since a community size of a trillion trillion would require much more than twenty doublings of growth. So these trends clearly have to break down at some point.

I’ve been exploring a particular scenario for this new era: it might be enabled and dominated by brain emulations, or “ems.” Interestingly, I had already estimated an em community size of roughly a trillion based on other considerations. Ems could take up much less physical space than do humans, and since ems could visit each other in virtual reality without moving physically, em community sizes would be less limited by travel congestion costs.

So what should one call a city of cities of a trillion souls? A “world”?

Something similar to the placebo effect occurs in many animals. … Siberian hamsters do little to fight an infection if the lights above their lab cage mimic the short days and long nights of winter. But changing the lighting pattern to give the impression of summer causes them to mount a full immune response.

Likewise, those people who think they are taking a drug but are really receiving a placebo can have a response which is twice that of those who receive no pills. In Siberian hamsters and people, intervention creates a mental cue that kick-starts the immune response. …

The Siberian hamster subconsciously acts on a cue that it is summer because food supplies to sustain an immune response are plentiful at that time of year. We subconsciously respond to treatment – even a sham one – because it comes with assurances that it will weaken the infection, allowing our immune response to succeed rapidly without straining the body’s resources. … Farming and other innovations in the past 10,000 years mean that many people have a stable food supply and can safely mount a full immune response at any time – but our subconscious switch has not yet adapted to this. (more)

OK, but the key question is: why would getting a placebo pill ever have been a credible signal that you could safely turn on your immune system? If for our ancestors treatments like pills tended to be very effective at improving health, you might think that a pill would give you so much extra energy that you could afford to spend some of that extra on your immune system. But pills are rarely that effective, and your body would quickly notice that fact.

My showing that you caretheory, that the main function of medicine is to signal concern, fits well here. The idea is that we are reassured by the fact that people take the trouble to take care of us.

The most severe part of our ancestors’ environment wasn’t the weather, it was other humans. When people were sick, they worried that their rivals and enemies would use that opportunity to hurt them. If such harms were coming, they had to be attentive, wary, and ready to act — they couldn’t afford to turn on their immune system, which would make them lethargic.

But if someone had caretakers, who spent time and other resources to take care of them when they were sick, why then such caretakers would probably also protect them from rivals. So they could afford to turn on their immune system. If your associates spend resources to buy you pills, and then take time to make sure you take certain pills at certain times, they probably care enough to protect you from rivals.

Two years ago I was persuaded by the book Sex At Dawn, at least on its “key claim, that forager females were sexually promiscuous.” While I didn’t buy authors’ free-love scenario, I thought our ancestors were much less tied to their sex partners than most folks realize:

A Hadza man hunts big game to look sexy, even though that retrieves less food. Except that when a women he has sex with has a kid he thinks is his, he’ll gather more but less-sexy food, to give this woman ~1/2 of her food for one year, ~1/4 for the next two years, and declining amounts thereafter. Now, yes, this may be more pair-bonding than in chimps or bonobos. But it is also far less than the farmer ideal of life-long monogamy! Many men today reluctant to marry for life would be ok with this level of commitment.

Lynn Saxon has a new book Sex At Dusk, quite critical of Sex At Dawn. She was a kind enough sent me a copy, which I’ve just read. Searching, I’ve only find positive reviews of it (here, here, here, here).

Saxon doesn’t write as well, and especially fails to summarize well. Even so, she does successfully undercut many Sex At Dawn arguments. In humans, sexual jealousy is a universal, females are picky about sex partners, penises aren’t over-sized, testes are small, sperm production slow, and the evidence doesn’t suggest a great deal of sperm competition. Female chimps have little extra-group sex, bonobos don’t usually mate face-to-face, and many Sex At Dawn quotes are misleading, given their context.

A recent study of female chimpanzees found no support for the sperm competition hypothesis: females did not produce calls when mating with low-ranked males so it was not about inviting other males to join the party, and calls did not correlate with fertility and the likelihood of conception. … Females called significantly more while mating with high-ranked males, but suppressed their calls if high-ranked females were nearby. …

[Researchers] found that [bonobo] females were more likely to call with male rather than female partners but the patterns of call usage were very similar in that females called more with high ranked partners (as in chimpanzees), regardless of the partner’s sex. With a female partner compilation calls were consistently produces only by the lower ranking of the two females. … In bonobos the increase in calls during the alpha female’s presense. (p.279-280)

Yes, it looks like chimp and bonobo sex calls are more brags than invitations. Even so, brags make little sense when it is common knowledge who has sex with whom. So a habit of similar bragging sex calls by human females would suggest that humans often didn’t know who was having sex with whom, suggesting a lot of promiscuity.

A key question, to me, is what percentage of our forager ancestor kids were fathered outside pair-bonds. That is, what fraction of kids were born to mothers without a main male partner, or had a father different from that partner. This number says a lot about the adaptive pressures our ancestors experienced related to various promiscuous and polyamorous arrangements today. And hence says a lot about how “natural” are such things.

Alas, none of these authors give a number, but my impression was that Saxon would estimate less than 20%, while the Sex At Dawn authors would estimate over 50%. Even 20% would be consistent with a lot of human promiscuity adaptations, such as female sex brag calls. I asked Saxon directly via email, however, and she declined to give a number – she says her main focus was to argue against Sex At Dawns‘ “paternity indifference” theory (that humans don’t care which kids are theirs). Which is fine – that is indeed a pretty crazy theory.

So where does the evidence sit on promiscuity? Our closest living relatives, chimps and bonobos, are quite promiscuous. Yes, their pair bonds much weaker than ours, and pair-bonding usually greatly reduces promiscuity. But few pair-bonded animals live in big social groups where hidden extra-pair sex is so easy to arrange, and humans live in even bigger groups than chimps or bonobos. For humans, we have lots of clear evidence of outside-pair sex, mate-guarding to prevent such, bragging sex cries, and desires for sexual variety. And humans do seem to spend a record fraction of their time thinking about and doing sex.

Since humans usually have clear overt norms against extra-pair sex, but strong urges to arrange covert sex, promiscuity estimates comes down in part to estimates of how well humans actually enforced their norms. My homo hypocritus theory suggests a lot of covert norm violation, and so a lot of promiscuity. So I’ll estimate the key promiscuity number in the 20-30% range.

Btw, here’s another fascinating quote from the book:

Hrdy writes about a startling interview with an old hunter in which he reminisces to a time when just the sound of his footsteps on the leaves of the forest floor struck terror in the hearts of old women. He was the socially sanctioned specialist in eliminating old women deemed no longer useful: coming up behind an old woman he would strike her on the head with his axe. (p.216)